What are the features of a shield volcano?
The features of a shield volcano include:
1. Broad, gently sloping shape: Shield volcanoes have a low, broad profile with gentle slopes. They are characterized by their resemblance to a warrior's shield lying on the ground.
2. Broad summit crater: At the summit of a shield volcano, there is typically a large crater. This crater is not very deep compared to other types of volcanoes.
3. Lava flows: Shield volcanoes are mainly built through the eruption of fluid, basaltic lava flows. These lava flows tend to have a low viscosity, allowing them to travel long distances from the vent before solidifying. As a result, shield volcanoes have extensive lava fields surrounding the volcano.
4. Vent location: The main vent of a shield volcano is located at or near the summit, where the volcano is built up by multiple eruptions over time.
5. Multiple vents: Shield volcanoes often have multiple secondary vents along their flanks, from which lava can flow and further contribute to the growth of the volcano.
6. Absence of explosive eruptions: Unlike stratovolcanoes, shield volcanoes typically do not have explosive eruptions. They are characterized by effusive eruptions, where lava flows out of the vent instead of being ejected forcefully.
7. Lack of steep-sided slopes: Unlike other types of volcanoes, shield volcanoes do not have steep-sided slopes. They have a gentle slope angle of less than 10 degrees, making them safer compared to stratovolcanoes.
8. Large size: Shield volcanoes are among the largest volcanoes on Earth. They can reach heights of several thousand meters and may have a width of tens of kilometers.
9. Hawaiian Islands: One of the most famous examples of shield volcanoes can be seen in the Hawaiian Islands, where each island is formed by one or more shield volcanoes. These volcanoes, such as Mauna Loa and Mauna Kea, are shield-shaped and have gently sloping profiles.